I. Field
The present invention relates generally to communication, and more specifically to techniques for transmitting signaling in a communication system.
II. Background
Communication systems are widely deployed to provide various communication services such as voice, packet data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users simultaneously by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.
A communication system may employ a transmission scheme with feedback to improve reliability for data transmission. For example, a transmitter may transmit a data packet to a receiver, which may send back an acknowledgment (ACK) if the packet is decoded correctly or a negative acknowledgment (NAK) if the packet is decoded in error. The transmitter uses the ACK feedback from the receiver to terminate the transmission of the decoded packet and uses the NAK feedback to retransmit all or a portion of the data packet. The transmitter is thus able to transmit just enough data for each packet based on the feedback from the receiver.
A base station in a multiple-access system may concurrently communicate with multiple terminals on the forward and reverse links at any given moment. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. The base station may receive data transmissions from multiple terminals simultaneously on the reverse link and may need to send multiple ACKs/NAKs in each time interval (e.g., each slot or frame) to these terminals. The base station may send the ACKs/NAKs to each individual terminal using unicast transmission. The ACKs/NAKs may be mapped to identifiers (IDs) assigned to the terminals, and each terminal can recover its ACKs/NAKs based on the terminal ID. Individual ACK/NAK transmissions for a large number of terminals may require an excessive amount of system resources, which is undesirable.
There is therefore a need in the art for techniques to more efficiently transmit ACKs/NAKs in a communication system.